SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a603135f118a1414a2bb17d506054e88f85ab975f0d83cf558267f02b01fb3b6' 
  AND token = 'Ywz4tV+BC6LlUfPd+8HOEIRZq7/LGvK91k/sy855qvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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