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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66e8dd3c9c20ff09b0fe9cd500ef27b7f7972269a9b1edbb9ed6a5ffdef8266c' 
  AND token = 'SbeI/ljMhEnLru4pFHUiITnj2bT29vDr7t+UGaMUl+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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