SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be97ffd85c52f9d4175eb677077d760f49485bb1bc63634fe1318d4fc73e53f6' 
  AND token = 'jefuipB5K+fwqQUJ/D1IvW82I9lo9KL3K0DY5IoTK+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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