SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2529a31306a07a3f9af5cdabd0cdbc3900621299b103f2c955d247d606087446' 
  AND token = 'F09P+Uk+nrCp5AYMcw51zRwOGMaxe3866NULdFlYJo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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