SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d7fe4c453e802543565327251b4905dbfdc1f6928e6b269d59954fd652ca048' 
  AND token = 'WBMuRgdBJ/kwG1/ckKWPywoyG0KJWIlLyZpvD2yN4OQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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