SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '058c5602da97f9096378eeab62fd8e418a6e4246c58a971c6954eab44cddd360' 
  AND token = 'cL3QoDjWw8EMOcJgsGPWWE69uSylEB/SOcbS6rn9gD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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