SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'befe43fd24c1b2949d5de948be03eeb2b35c308c538b4d109bcf15e47dcd81b2' 
  AND token = 'keCIuJgDVQJOoBPm68LQFnvhqUYcuLYLMGhgTMKq898=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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