SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd29660fdcb356e6941899bb5a881906be03183656b986638f3648ff356480a05' 
  AND token = 'IRCdDpU3qLrUBrS5c9JcwMHX6Wb2rmHFYElOdB+29ZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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