SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd42f055722e5604c08fadff0051714a3226660391993fa6884ea3d7351bbd9dc' 
  AND token = 'Hzv16wYEp3uNnDW6ZvzmOHxKbdSwW7klIC4/WdrWn18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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