SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbb714baa89acdb378f79ed61c8bf4fe0be9a851a32c971343bc85b748075930' 
  AND token = 'FVqXCYlWyxecPR54JtsQPxPdolmcbXW9zdSTXRaxSzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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