SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd52ff65b3253d55a181064cfa6e8c0c5ae7c59f51cb1fe85e8fb1da75dd3b37c' 
  AND token = 'Fwq9DAcGupTb15ZCGnDqNGQ8iKdAMEIlJUf3RMrNZGc=' 
  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"
    }
  }
}