SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a597a095e22baeb44895c04f418c7953464a4583b765f8696224811a2e6f3913' 
  AND token = 'R8+oKo6JO3bWG0YE89W0JVfOrWulVTlfLNDLGeBxKAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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