SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd3439f9ec955723853a802f4c79bae61fd5b0159b5df0f7a2446bba766d15c9' 
  AND token = 'KRquy5osCaedDTGkm95KXOEJUcYKU+2/JTUbjcTQbso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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