SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '389abe973336ca7e3a402b44479f353a17c2a84d8d1fec7cfd1d69fff455cb3e' 
  AND token = '0XwcnySSeqa1WAAjGymCsKUTdLFzrIALn7h0cY+9Tvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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