SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a09b2c14559e5dee32137a2b10bf868e7cf0b02c6c8052c34374cc9dcb7a947c' 
  AND token = 'xwUK/bAODfuJ1Fo8Pq2YiqGYn57C2LK1cLmz/bp+6QQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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