SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b94662cedb8225be04fb1026e6a4995176b980f3f1ddf8a5c03197d192433b1d' 
  AND token = 'CX+uhZX4goHBRLJYilQ4EpIhFtolcSB4YDyjBmV39W0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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