SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdd02ba476455023a86c89f0b336433f9f09edce0723e5b21b8263cadddb647e' 
  AND token = '94SAGgKotOCRrp+2fq5yNpfqQwLgE8msRDcTiFdk6QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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