SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2da09ce2f548241a6be316f35de86818b5407ccf98c3e3869b25b311ccf75091' 
  AND token = '0LS9P1g3wnDGg8lLD8zTqpvClhc21V7jL6XBfvWpdQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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