SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b98f193fdf065e3bcca1e99565e4edd62380dc8b0df70d03fb4425a45aaa3ff' 
  AND token = 'PaCyciXR1isiyM9fp9184FEWfMQTPudoG/ARMDSKei8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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