SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e98a6a9815f32d28791f510a8946b5c921e0bafb2f658cd1e524b410276f05f' 
  AND token = 'AoL/Fzcw3IF7+1aP1FPio1LdvpV8hvUMGCy/qlQnRhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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