SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a313302e9cb1ce0266525ac8f9f31e253040b419c04ef90e7fbb8703888efbfe' 
  AND token = 'jV5zMX+5GzRvHToX8QrqWGr3KwFNLx2mEcg5uHprLJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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