SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f338ea80ee1267f6cef52164e2471fdcaaebe1623f5be7e36cf26bdf4ca05492' 
  AND token = 'lkFmwtF0KMLdveqaX+mxkVTWmuKpgU+43UGvg4RqYXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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