SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1c7d188cb06cea888bfa37ef3c57651228bcf6bcce5346622f52195fac1ca3' 
  AND token = 'RlJOSUi3dnk43X5IpiQn5BYGZvalqLUiEa1DuuDkNAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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