SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9a077016e6a79c1d75f7c5ece00b8f46cfd4b84276e19b589a3fc056714a52' 
  AND token = '+PVDJZXOg6jjFCRPtKt/VDU357VUapS1BW2zBhQqraM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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