SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e526f365401a75955da1e553f7562786442b7a631278c3b63ac840645f92bf67' 
  AND token = 'chi3KZEHwWmVWn2Vpgik8/6eGp+X7ZX9NG7ePz+MhfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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