SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '656eea21fb2732d96c38b666398ea2d0e774d2890f19a915b4a1c3ed3db5a68f' 
  AND token = 'JTThwuOtIn1xRpBA2r1EcTjL5V1YWdA6nALhoo9w5Ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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