SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6b129abd3bb1fa8754fdb62f8c52fc5ab2dc5b69f7cbd59ff7889a9db77e9d9' 
  AND token = 'vSTTppC/js0GWIcZkBGrqcKEtFI+fH+tVONgAVJIgFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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