SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a458967bb2a142e48bc36b5c2dbcfd5d74cb9e2338487a1fa64b62467d9d535d' 
  AND token = 'xMBldKg6HVwGcx/OfTL80QnZElpS7z+2rAny073AyNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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