SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0abf09848dc855e91200530873844b2e1fe91d481adf11300e0630b5c910c12b' 
  AND token = '8hJC+qlLx6ziNj3EnkVYxbzXFmg5zwwQKPeYuA5buTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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