SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '78461e2838e1de79e09b48e189ab50ac39f38876e5a5155ef1dbe779c907a87f' 
  AND token = 'fSeASCPvlArcBUgy53zNEB+Il+CL0aGww9VUJC/vSx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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