SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c97803c5923860b35556e0bf81338ea93cd90996e6b018632f6cf520afdbb6d4' 
  AND token = 'RP7/8zZD+xUplF7JGsCcrhCAYyfe/KYv+Sjs549i6VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}