SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b8fb78ae7c02c9dd1765a00827ef367c7db948c9c3d9ac6b3932c7ecb9e9e0b' 
  AND token = 'q+vsUrT+A/sMbocc/JiSlEjQlucB5SYFo5QHYFItx24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}