SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c3dc154434b4490ebaf9dc63600b29948fb8da68fc31d399d3411c01c60c0c5' 
  AND token = 'muopkR193Gobzi7V2IQqObSTeD1kKPQWoZ7fh1UwScA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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