SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d3e68ffd340091010b2ad32122f9824e1f2f3e36ab13269411e912e33c9cd0' 
  AND token = 'WB+JfPVZfJB6WmvGZkItwcpZeHVoPKrivyS5V8Iyj4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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