SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0b6fd79fb2e200130bf6928b357fabc796b4edd0e0c8090231bfc528c4a8201' 
  AND token = 'wwSI/tI34M/VYr+GxJ6UvBPACMG+v2DCGgBSr4bsTzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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