SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08b481db21dc9b268a7ef57973c07e87ef0e81db28a1dea23d188243edadd02b' 
  AND token = '/5lwhU1J2NJZ16IJiFohy56MCYPQrs+jdaS/mJLWuWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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