SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eca5d32efef5f37dd06795f3c27459b2952ee7346835d1b9b97fdd8b54affc1e' 
  AND token = '+O6yRq/00E0A6AVD0+dyhq6nN+e7qZBM2RaKgWWxQOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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