SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69cce50aeb7c664ba1c0f00e3181fb99e9e5e6640311b2ccd62984a6b760ffc8' 
  AND token = 'I2LAZYAvxlpAvsy40kLUXqFznOQOnSClPtUtumifXI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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