SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b935906a100e513e434abe1bdbb0f43c6e8be06bbab3703b8337bfb079295839' 
  AND token = 'Y7T7pIbuKM4R9i2QP1sqBDGA5ejUWAXxPCS9xxEflEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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