SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cdb814c4e58a7099cec9b8f92eb3592c43434b8f508e35aa084cbcbef174b46' 
  AND token = '+DYKXEsZs0zbf6q/zD7d98UT6vMBWLAqHJkBjYuHyWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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