SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85a3c561840f2a67593138827550fd392c222009f0bf4a37c3a0e0355157de0b' 
  AND token = 'V+1J3jmGGaofbwV/F0AuFsrljZ9ZBg5H7QU2cp1P5/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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