SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a75d0835503a49a6c88a61dfb9ffcb41bb06c24dab9fcc252ab9731860ef173f' 
  AND token = 'Q5pygOK+/RRpTh4YBHAyKc09wcxz65fISLIEIhluLF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}