SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f22de6af4d06682ade1c38eb504f353a07afce5d20bc54e8d747591a7adefe5' 
  AND token = '1uZfFAE/glh3JbHwFtElJ/gNqRsfYUbtdi6xA86YT70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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