SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afcd1297d50971ee896bcf69a088cdad4ca6ff9d3aaf5fdab3fe144e19fbc30c' 
  AND token = 'f+rhrmsScHpdb/cJO7IqUXvOCQ1shgY1gvTULwTGSr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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