SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a45f7f3787353253034d4e1f0cfd069ea601d2fcc94adeec813fbdbb45a7a344' 
  AND token = 'aw4n/jXhboS0KGdb1tFKFOatLcFD6UoUbbbk47sw3aU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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