SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eace7e55306284dd6855b1171c80e1847faa6861af2bca3975dddb72c8ea44f0' 
  AND token = 'fSK70243dafy5jR8FUpwQfDj6kAZfTGkPFyxwbRZcdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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