SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caf5a90d8a7b06c1c25ddb2e773c3e159df25c75888cbcb226db78936d714ae9' 
  AND token = '9/CiSF9NGJqTMjwZzsSHxZnskHlp9dr+5FSYu1zhNbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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