SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a84dd3e7274c5de743eae64de22915f811413dc7eebfcda2953812f7a2e159b' 
  AND token = 'bzhQsGEzo+fV7B6M23Hdrsmv7Zr7FeOE8m0geKrN97A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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