SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caec641c3e6854023108921ea9cbca2c303c4db32dccd9686f7a9bceedf3c452' 
  AND token = 'vUzfwzfyC0jmO2U86TNn1mWwaYzorseqVrbywNrm9So=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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