SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80cfbd166fad9be05836e52cde98b039517110c79d8258007056a0feadecce09' 
  AND token = '7J37JOMdtIBFDOCwmLQEjP9JMETzdwJiZbIa9bOse6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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