SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6fee5acf7b3ab8a24355642563e5e5d608fbad9673c13eab1e4f8bc4fddd5c2' 
  AND token = 'AFwzuAmUDbdEKXoGKX8nvHf1z6EgwqZnQvGoUG1SNJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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