SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af8d915ec35a1c0a095c1f504ecb1d248f663d5f61cb17722c104bbfeec3a425' 
  AND token = 'BPme+M/yJQt/Msg49XNwFwlY10cuANpN1fcidrQNcqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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