SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66447195ad31088008a3424d5dd5cbddf678d7bb16a58867a99c997a3b898f81' 
  AND token = 'RhxhWFlF0OIxnpVTeR4v3MR8mcKmweR4hcH11yAhVZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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