SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e14f84eb01d08daeb15325ed9a1a28f57691fde2abf205c4c89607eaefe04e86' 
  AND token = 'tQ5O4loVCR5gQz1CbYECEBbsfiwz0pSFfkZTeUos1l8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00007

JSON explain

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